Emphatic no. On the other hand Mauser actions are the most copied....often simplified as Arisaka Types 38 and 99 prove. The Swiss Karabiner K-31 with straight pull proves that there are other concepts.

According to my dad mauser action was the ONLY action. He was very knowledgeable and aware of other actions but considered mauser cockonopenorcockonclose the `O` & the `I` of all actions. Some people use `mauser action` like a lot of people use `crescent` wrench.

No. The Mauser action for the most part is a bolt that has two locking lugs at the front of the bolt. Vs locking with the lever Vs locking at the rear Vs locking in some other manner. The Mauser action is cheap to produce and works reliably.

NO. The Russian M91 Moisin for example has locking lugs at about right angle to Mauser bolt location., lot of them made and still in use. 'Split Bridge' Mannlicher another different lock up with base of bolt acting as locking lug. Lee- Enfield has locking lugs to rear of bolt and receiver, lot of number 3s and number 4s made for WW1 and WW@, some still in use with former commonwealth, colonial militaries and police forces. French Berthier and Lebels have different magazines and 'split bridge' receiver, French M36 has one piece bolt but rear locking lugs. Mauser K98 action with controlled feed is base for Winchester M70, new Ruger and some other copies from BSA, Japanese contractors for 'Sporting Arms'. some multiple lug designs with 3 or 4 much smaller lugs at rear or front, Savage 340 has something like old Krag- one forward lug and rear lug is base of bolt. Mauser pattern in sporting arms- maybe 1/3 to 1/2 of sporting rifle production if you count Win M70 and Ruger copy as 'Mauser'.

No, but Mauser set the standard for all bolt action rifles that came afterwards when he introduced his iconic rifle that would be designated Gewehr 98 or G98. Rifle makers started to use some or all of his innovations in either direct copy or in some modified form.

In one instance, Mauser sued the US Army (and won) for the Springfield M1903 because of violating Mauser's patent.

In other areas, using multiple locking lugs has become the standard for most locking breech rifles. Mauser used a setup of 2 lugs on the front of the bolt with a spare/safety lug towards the rear of the bolt in case of failure of the lugs in the front. As strange as it sounds, before Mauser there were rifles with only 1 or no locking lugs and this meant if a lug or whatever locking mechanism failed, the bolt comes flying back into the shooter's face.

Another concept/innovation copied from Mauser is venting gas away from the shooter's face. In his day, ammunition case were notorious for rupturing. While it didn't happen with every round, the frequency was high enough that there was a real danger of super hot gas from a ruptured case blowing back into the shooter's face. Think of a blowtorch blowing in your face and you get the idea. Mauser designed his G98 in such a way that gas from a ruptured case is not only redirect away through vent holes, but was shielded to blow away.to the sides or upwards. This idea in a different form is used on the AK47.

So while not every bolt action rifle is a Mauser action, it would be very hard to find one that is not influenced by some aspect of Mauser's G98.